/* pixel.c 25.4.6             */
/* From Amiga C for Beginners */
/* by Abacus                  */

#include <exec/types.h>
#include <intuition/intuition.h>

extern struct Window *OpenWindow(); /* Declaration */
extern long *OpenLibrary();  /* Hello Aztec-User! */
extern double sin();

struct IntuitionBase *IntuitionBase;
struct GfxBase *GfxBase; 

#define INTUITION_REV 0
#define GRAPHICS_REV 0

/* Number of colors of Workbench */
#define WB_COLORS 4

struct NewWindow NewWindow =
{
   10, 50,   /* X and Y Position */
   360, 120, /* Width, Height */
   3, 2,     /* Color Indexes */
   NULL,
   SMART_REFRESH | ACTIVATE | WINDOWDRAG | WINDOWDEPTH,
   NULL,
   NULL,
   "This Line is changed!",
   NULL,
   NULL,
   0, 0,
   640, 200, /* PAL users - change 200 to 256 */
   WBENCHSCREEN
};


main()
{
   struct Window *Window;
   register struct RastPort *r;
   register int i, j, top, yoffset;
   int i_to, j_to, color, colors[512];
   double factor;

   if((IntuitionBase = (struct IntuitionBase *)
     OpenLibrary("intuition.library", INTUITION_REV))
      == NULL)
     exit(FALSE);

   if((GfxBase = (struct GfxBase *)
     OpenLibrary("graphics.library", GRAPHICS_REV) )
       == NULL)
      exit(FALSE);

   if((Window = OpenWindow(&NewWindow)) == NULL)
     exit (FALSE);

   r = Window->RPort;
   top = Window->Height / 4;
   factor = 2 * 3.1415926 / Window->Width * 1.5;
     /* 1.5 Sine Waves */

   for(i = 2, i_to = Window->Width - 2; i < i_to; i++)
     {
        for(j = 0; j < top; j++) /* A vertical line */
          {         /* Transfer to Array */
               color = ReadPixel(r, i, j);
               if(++color == WB_COLORS)
                  colors[j] = 0;
               else
                  colors[j] = color;
                  /* increase color index by one */
         }
        for(j = 0,
           yoffset = top + top * sin(factor * i) + 16;
           j < top; j++)
           if(colors[j])  /* If Pixel should be set */
             {
                SetAPen(r, colors[j]);
                WritePixel(r, i, j + yoffset);
             }
     }
   Delay(1500);    /* Wait 1500 Ticks = 30 seconds */
   CloseWindow(Window);
   CloseLibrary(GfxBase);
   CloseLibrary(IntuitionBase);
   exit(TRUE);
}